Nitro ketals and process for preparation thereof



Patented Aug. 27, 1946 I -UNITED- ST ATES" PATENT OFFICE J NITRO KETALS m teams Fort PREPARATION 'rHEaEo v Glen II. Morey, Terre Haute, Ind assignor to Commercial Solvents Corporation, Terre Ilaute, Ind., a corporation of Maryland No Drawing. Application at 29, 19.44, p "1 Serial No. 547,2 3 g I R N 02 wherein the substituent R may be either hydrogen or alkyl, and R represents an alkyl group. Compounds of the above type are prepared by reacting a suitable 2-nitro-1,3-propanediol with an alkyl levulinate in the presencefof' a small" quantity of acid catalyst. The process is of an'inert water-'immiscibleli'quidsuch asben zene, toluene or a similar substance in order 'to substantially a'sit is mixture is preferably" removethe water produced formed. The reaction heated at its reflux temperature until approximately the theoretical quantity of water has-been removed. Thereafter, distillation is 'dis'continued;

and the mixture washed with water to-remove the catalyst. Separation of the inert water-immiscible liquid and water, as well as otherimpurities is readily accomplished by distillation. The inert liquid and Water are removed at atmospheric pressure, while the higher boiling impurities, such as, unreacted alkyl levulinate or 2-nitro-1,3-pro panediol are separated from the ketal thus produced by distillation under reduced pressure. Further purification of the desired product which is obtained as a residue may be readily effected by distillation under relatively high vacuum.

One of the highly surprising features of the process of the present invention is the fact that said process has been found to be operative only with 2-nitro-1,3-propanediols. Attempts to carry out the same type of reaction with the ordinary glycols such as ethylene glycol or with the trihydric nitro alcohols, such as, tris(hydroxymethyl) nitromethane have been completely without success. With the ordinary glycols, comp1ex mix tures of products are obtained, which cannot be separated, whereas, with compounds such as tris- (hydroxymethyl) nitromethane, no reaction whatever was observed to occur. In the case of the 2'- nitro-1,3-propanedio1s, however, the reaction involved appears to be quite general and is readily relates to aseries of new preferably? eifec'ted by heating the reaction mixture in the prsence 8 Claims. (01. 260-338) effected between any alkyl nitrol 3 propanediol.

The acid catalyst utilized in producing the new I ketals of my invention may be selected froma rel- -"atively wide range of compounds. In fact, it may generally be saidthat any acid previously known to be capable of promoting esterification will be satisfactory for my purpose. Specific examples of such acids are: p-toluene-sulfonic' acid, sulfuric Y wide variety of compounds.- Typical examples of acid, hydrochloric acid, and the like.

The alkyl levulinates and 2-nitro-1,3-propanediols employed in carrying'out the process of the present invention likewise maybe selected from a alkyl levulinates operative in my process are methyl levulinate, butyl levulinate, hexyl'levulinate, decyl levulinate, and the like.v Examples of suitable 2-nitro-1,3-propanedi0ls are 2-nitro-1,3-

propanediol, 2-nitro-2-methy1-1,3-propanediol;2-

nitric-2"-ethyI-L3-propandiol, ,2 nitro-2-propyl- 1,3-propanediol, 2-nitro 2-butyl-1,3-propanedioh;

and the like.

My invention may be furtherillustrated by the following specific examples:

Example To a mixture consisting of 149 g. of '2-ethyl-2- nitro-1,3-propanediol, 200 g. of butyl levulinate and 300 .cc. of benzene, was added 1 g. of paratoluene sulfonic acid. This mixture was then heated to reflux temperature and the Water produced during the ketalizationremoved with benzene, th latter being continuously returned to the distillation flask. After about twenty-four hours, 16.5 cc. of water was removed, heating was then discontinued, and the mixture washed with cold water. The major portion of the benzene was then distilled off at atmospheric pressure while the last portions thereof were removed at C. (30 mm.). The crude butyl-2-methyl-5- ethyl-5-nitro-2-m-dioxanepropionate was then distilled in vacuo. A fraction was collected below C. (5 mm.) and consisted chiefly of unre-' acted butyl levulinate. The pure ketal boiled at C. (3 mm.) and amounted to 219 g. corresponding to a yield of 72% of theory.

Analysis: Calculated for C12H25NO6- N, 4.62.

. Found: N, 5.15.

Example II levulinate and any 2- dioxane-propionate'.

propionate. I V

V 4'.;In a process forthe preparation'ofgsub stituted -S-nitro--l,3+dioxanes having the formula:

the presence of line compound, melting at 83 C; and was obtained in a yield corresponding to 60% of theory. Analysis: Calculated for C12H21NOsN, 5.09.

Found: N, 5.66. Molecular weight: found 269;

theory, 275.

approximately 1 g. of sulfuric acid. The product thus obtained was a crystal- It is to be specifically understood that I in no Way desire to limit the compounds disclosed in the specific. examples given above. On the contrary,

the present invention to 1' -tuted. 5,-nitro-1,3-dioxanes of the formula: as previously. in-. e a

dicated, the process involved is generally applicable to any alkyl levulinate and any 2-nitro+1,3-

propanediol.

The new ketals of the present inventionhavef been found to be useful as placticizers for various film forming materials, particularly thosecona 1. Substituted 5.-nitro'-l,3-dioxanes the i following general formula;

wherein thesubstituent B. represents, a. member selected fromthe group-consistmg: of; hydrogen and alkyl and R is alkyl, a

2. Butyl 2 methyl 5 ethyl 5 intro-2 min which the substituent R represents a member selected from the and alkyl. and B is alkyl, the steps which com:-

will be readily havingbeen described; what.

5-ethyl-5-nitro-2-msdioxane class consisting of hydrogen prise mixing a Z-nitro-lfi- -propanediol with an reilkyllevulinateinthe presence of an esterifica heating the resultant prise mixing a 2-n itro-1,3-pr0panedio1 with an alkyl levulinate in the presence of an esterification catalyst and an inert water-immiscible liquid, heating the resultant mixtureto its reflux temperature, removing'the water in a vaporous state with said water-immiscibleliquiaand.

substituted" 5-nitro-1,3- 7

recovering the aforesaid dioxane.

5. In a process for the preparation of substiimeg: on, e

NOn

' in'which the substituent B. represents a member selected from the group consistingof hydrogen and alkyl; and R is alkyl, the steps whichcomprise mixing an alkyl levulinate with a 2nitro V l;3'-propanediol;in the presence of an'esterifica' heating .the resultant mixture and tion catalysir recovering a compound of? the aforesaid g-formula.

6. In "a process for stituted 5-nitro-1,3,=dioxanes in which the substituentLR represents a member selected from'the group consisting of hydrogen is alkyl, the: steps-which comtion catalystandrbenzene, n 7 mixture to its reflux temperature, removingrthe water inayaporous state with said benzene and recovering'the aforesaid substituted 5nitro 1,3-

dioxane. v

. '1. Theprocessof claim 6 in which the alkyllevulinate is butyl levulinate and the -2-nitro-1=,3-v

propanediol is 2-nitro-2-ethyl-1,3-propanediol.

'8; The process of claim 6 in which the alkyl levulinate is ethyl levulinate and the 2-nitro-l,3-

propanediol is 2-nitro-2-ethyl-1,3-propanediol.

' GLEN I-I. MOREY.

the preparation of; sub-,-

of the formula: V 

